Touch screen is a touch-sensible screen that the user can directly operate elements on the screen. Due to the intuitive way of operation, touch screen has gained great popularity. Currently, touch screen is widely applied to many electronic devices such as a touch phone, a smartphone, or a personal digital assistance (PDA) phone.
As touch screen is activated by touch, accidental touch errors may occur easily. Let the touch phone be taken for example, when an incoming call is received, an answering button and a rejecting button are shown on the touch screen for the user to choose to answer or reject the call by click the answering button or the rejecting button, respectively. However, the answering button or the rejecting button may be accidentally touched by the user or by other objects and cause unintentionally answering or rejecting the call, and result in great inconvenience.